3ds Max, no question; just not version 2013. The FSX and P3D sdks are designed to work with Max, although if you're using a recent version you'll need the P3D sdks only. Lucky you!

The paintkit is what the designer makes it: that's where a lot of developer time goes that the new modeller doesn't expect and it's down to him or her to make a useable paintkit. UV automatic unwrap used without thinking on the exterior mapping is what leads to jigsaw puzzles.

Blender! since it has been designed for more than just "the task of modeling FSX aircraft". And with the Blender2FSX toolkit you can export your Blender models into FSX
Ok, Blender has a steep learning curve, but it is oh so rewarding when your truly master this wonderful free program.
Lucky for you, the Internet ( and Youtube/ Vimeo) are filled with excellent and free Blender tutorials and communities that can help you get started.

The tool doesn't matter, so long as it can export in the format that you want. Certain tools might make some tasks easier (there are people working in oil and watercolour who will match anything that 3DS or Lightwave or Cinema4D can do, but it takes a lot more time and effort). Having a render engine is definitely easier than hand-drawing shadows, highlights, and so on. What does matter is that you get the basic shape right first before adding details, plan ahead, observe reality carefully, and treat all sources with a healthy dose of skepticism.

I recommend starting with something simple. An early Learjet or a DC-9 is ideal if you want to build jets. In terms of shape, they're about as simple as airplanes get. You might not even want to release your first project outside of a bit of sharing with a small group of friends, and there's nothing wrong with that. I do not recommend the now-common "I just downloaded Blender (or pirated 3DS) and now I'm going to make a big payware airliner!" route. Don't bite off more than you can chew, and, by all means, don't be afraid to ask for help.

What a funny response. The OP asks what the best proggy is for design, and tells us he already OWNS the program used by the developers of the sim. He already owns the program that the SDK references...but.....

You suggest he experience a long learning curve just to switch to a program you like? How can you defend that, especially with your logic of avoiding design tools that ONLY build fsx aircraft?? Who ever heard of a tool that only builds fsx aircraft?

What's obviously best for the OP is to use what he has, its the design program used by and intended by the makers of the sim. The reasons NOT to use 3dsmax are cost (not an issue here), and learning curve if you have only experienced something else (not clearly an issue here).

Yeah I have 3ds and have had a couple experiences rendering 3D aircraft to paint liveries on them for fun

I will be focusing on a small aircraft first to get the hang of things since I'd like to make it the best quality possible (although I'm just going to make it for me currently )

I just have a couple more questions to get the idea of how things work,

1. From one format (SDK?) can I convert it for use in FSX, P3D and FS2004? I've noticed that some model kits are sold FSX and P3D together and FS2004 separately. I use FSX but just wanted to know about this.

2. Do things such as the emergency slide rafts have to be rendered in separately and then added later and can they be animated to inflate unlike the captain sim ones which just appear?

3. Do doors have to be designed in a certain way if you want them to be controllable? (open/closed) Also landing gear? (like how would you tell certain parts to animate when needed, with code of course but do you need to build them in a certain way?)

4. Is it easy to design a cabin? I've done some livery designing for myself (and used 3ds to make 3D rendering of aircraft with my designs) I'd like to make a version of a 737 or A320 for example with how my own airline would have seats arranged, sizes, colors, classes and galleys etc. (this ill only do once I've successfully designed a couple of aircraft tough ) Although I'd even like to make my own cabin on my first small aircraft, how easy is this? Does it need any special things or can I just render it inside my plane?

You're kidding. 3ds Max is just for FSX modelling? It's one of the standard packages for all sorts of game development, of which FSX is a very small part indeed. Not to mention CGI enhancements to films and TV.

Might as well say Photoshop is for adding funky captions to your holiday snaps.

What a funny response. The OP asks what the best proggy is for design, and tells us he already OWNS the program used by the developers of the sim. He already owns the program that the SDK references...but.....You suggest he experience a long learning curve just to switch to a program you like? How can you defend that, especially with your logic of avoiding design tools that ONLY build fsx aircraft?? Who ever heard of a tool that only builds fsx aircraft? What's obviously best for the OP is to use what he has, its the design program used by and intended by the makers of the sim. The reasons NOT to use 3dsmax are cost (not an issue here), and learning curve if you have only experienced something else (not clearly an issue here).

Thanks Bob5568 for your correct feedback about my over-enthousiastic reply to the OP's question. I saw the word Blender (a program that I love to use) and... overlooked the fact that the OP already had experience with other modeling programs ass well.
I fully agree with your statement "...is to use what he has, its the design program used by and intended by the makers of the sim...."

You're kidding. 3ds Max is just for FSX modelling? It's one of the standard packages for all sorts of game development, of which FSX is a very small part indeed. Not to mention CGI enhancements to films and TV.

Yeah I have 3ds and have had a couple experiences rendering 3D aircraft to paint liveries on them for fun

I will be focusing on a small aircraft first to get the hang of things since I'd like to make it the best quality possible (although I'm just going to make it for me currently )

I just have a couple more questions to get the idea of how things work,

1. From one format (SDK?) can I convert it for use in FSX, P3D and FS2004? I've noticed that some model kits are sold FSX and P3D together and FS2004 separately. I use FSX but just wanted to know about this.

2. Do things such as the emergency slide rafts have to be rendered in separately and then added later and can they be animated to inflate unlike the captain sim ones which just appear?

3. Do doors have to be designed in a certain way if you want them to be controllable? (open/closed) Also landing gear? (like how would you tell certain parts to animate when needed, with code of course but do you need to build them in a certain way?)

4. Is it easy to design a cabin? I've done some livery designing for myself (and used 3ds to make 3D rendering of aircraft with my designs) I'd like to make a version of a 737 or A320 for example with how my own airline would have seats arranged, sizes, colors, classes and galleys etc. (this ill only do once I've successfully designed a couple of aircraft tough ) Although I'd even like to make my own cabin on my first small aircraft, how easy is this? Does it need any special things or can I just render it inside my plane?

Getting back to Tom.....Others are best to answer these questions, but I'll take a stab. I'm guessing you are pretty new around here, and may not know about the wiki. It contains a wealth of knowledge, and I recommend you do some reading, then come back with specific questions. Start here..

You'll note at the bottom of the page are filters for various sim versions. No one has made it completely simple to create models for all versions, you'll need various sets of gamepacks, but start with the wiki....I think this stuff is all covered there.

Others are best to answer these questions, but I'll take a stab. I'm guessing you are pretty new around here, and may not know about the wiki. It contains a wealth of knowledge, and I recommend you do some reading, then come back with specific questions. Start here..

Well, the latest versions are supported by the P3D SDK (I KNOW 2015 is, I've heard that 2016 works, I can't swear to 2017). Older than that are typically supported by P3D. The P3D is the next incarnation of Flight Sim, developed by Lockheed, but the P3D SDK ver 1.4 (I think) is what we need to use if our max versions are this reason. I suspect I'm getting some of this twisted, and the WIKI probably spells it out. Its like ordering food ala-carte. Go to the P3D sdk link below, and read the revision details for the various SDKs...they talk about which max versions they support.

Arno, Tic, Dick, or anyone???? Tom could really use that cool chart someone posted a while back that showed the options for the various compiling tools required based on the various sims. Tom needs it, and I did a quick look at the wiki, and didn't see it.

UPDATE: Just read over the data on P3D version 3.4 SDK, and it indicates support for max 2017!

Thanks bob I'm using FSX but is the P3D SDK compatible with FSX? A user posted above that on a 3ds version above 2013 you only need the P3D SDK and as I said above I've seen aircraft packs for sale as FSX + P3D and FS2004 sold separately

Thanks bob I'm using FSX but is the P3D SDK compatible with FSX? A user posted above that on a 3ds version above 2013 you only need the P3D SDK and as I said above I've seen aircraft packs for sale as FSX + P3D and FS2004 sold separately

P3Dv1.4 versus P3Dv2.x are like FS9 versus FSX; they are very similar, yet very different programs.

Creating models for any of the flight simulator programs is a two step process:

Exporting the mesh from Max to the intermediate format .x and .xanim files; .x is the mesh and texture materials, .xanim has the animation data.

Compiling the intermediate .x and .xanim files to a complete exterior or interior model (.mdl) file.

Step one is accomplished using the specific export module coded for each version of Max. For example for my Max2012 64bit version I have to use Max2012_FSModelExp_x64.dle from the P3Dv2.4 SDK. Regardless of which version of the export module, the resulting .x and .xanim files are identical.

Step two is accomplished by using the specific compiler module (XToMDL.exe) that was coded for a specific flight simulator platform.

It is the compiling step that requires having the two P3D SDKs. As stated twice in this thread, P3Dv1.4 will compile "FSX compatible" models for both FSX and P3D (any version), whereas P3D v2.4 will compile models only for P3Dv2.x, meaning only "P3D native" models.